If you do not supply the -y option, you will be prompted for comments.

Of course, this all assumes you want to make this a changeset. For example, if you just wanted to make a personal preference configuration change, I would suggest that you put that into ~/.bk/config instead.

You haven't said what is failing or provided error messages... so I'll answer blind.

Yes, I'm sorry that was an awful bug report. What hadn't occurred to me was that I would have to call bk edit BitKeeper/etc/config first.

What was (seemingly) the problem was that commit, citool and checkintool were telling me there were no changes.

Of course, this all assumes you want to make this a changeset. For example, if you just wanted to make a personal preference configuration change, I would suggest that you put that into ~/.bk/config instead.